Multi-lumen catheters and methods for using same

ABSTRACT

Multi-lumen balloons for use as or in conjunction with balloon dilation catheters, and methods for making such balloons, are disclosed.

The present invention relates generally to balloons and ballooncatheters for internal body applications, and more particularly, toballoons having a plurality of lumens through which to access either thedistal end of the catheter shaft or internal body-locations, and tomethods of making such multi-lumen balloons.

BACKGROUND OF THE INVENTION

The use and construction of balloon catheters is well known in themedical art, as described for example in U.S. Pat. No. Re. 32,983 (Levy)and U.S. Pat. No. 4,820,349 (Saab). Balloon catheters are typicallyutilized as dilatation devices for dilating a blood vessel, e.g. acoronary artery, or other body cavity, although other uses have beendeveloped, e.g., temporarily anchoring an instrument within a body lumenso that a surgical or therapeutic procedure can be performed. Otherpatents generally showing the application of various types of ballooncatheters include U.S. Pat. No. 4,540,404 (Wolvek), U.S. Pat. No.4,422,447 (Schiff), and U.S. Pat. No. 4,681,092 (Cho et al.).

It is also well known in the medical art to employ catheters havingshafts formed with a plurality of lumens in instances where it isnecessary or desirable to access the distal end of the catheter or aparticular internal body location simultaneously through two or morephysically separate passageways. For example, U.S. Pat. No. 4,576,772(Carpenter) is directed to increasing the flexibility: orarticulatability of a catheter having a shaft formed with a plurality oflumens that provide distinct conduits for articulating wires, glassfiber bundles, irrigation, and vacuum means.

It is also known, as shown in U.S. Pat. No. 4,299,226 (Banka) and U.S.Pat. No. 4,869,263 (Segal et al.), to employ multi-lumen catheters witha balloon. The Banka patent shows a double-lumen catheter shaft ofcoaxial construction wherein the outer lumen carries saline solution toinflate a balloon, and an inner lumen, located coaxially inside theouter lumen, is adapted to receive a stylet or guide wire. In the Bankapatent, the double-lumen dilatation catheter is designed to be coaxiallycontained within the single lumen of a larger diameter guide catheter.

The Segal et al. patent shows a more complex dilatation catheter havingfive separate, non-coaxial lumens (FIGS. 1 and 2) extending through thecatheter shaft, including a balloon inflation lumen 18, a distal lumen17, a wire lumen 22, a pulmonary artery lumen 26, and a rightventricular lumen 28. Lumens 17 and 18 extend the entire length of thecatheter shaft from the proximal extremity to the distal extremity.Lumen 17 exits through the distal extremity 14 b of the catheter shaft.The distal extremity of lumen 18 is in communication with the interiorof balloon 16 to permit inflation and deflation. Lumens 22, 26 and 28,on the other hand, only pass partly or completely through the largerdiameter, proximal portion 14 a of the catheter shaft. A transducer 21mounted at the transition-between portions 14 a and 14 b is coupled tocircuitry by wires 24 extending through wire lumen 22. Proximal portion14 a is stated to have a diameter of, for example, 0.098 inches whereasdistal portion 14 b has a diameter, for example, of 0.060 inches. TheSegal et al. catheters are prepared by extrusion (col. 2, lines 53-54).

In the above-cited prior art, it should be appreciated that the term“multi-lumen” in the phrase “multi-lumen balloon catheters” means thatthe catheter shaft is multi-lumen (as opposed to the balloon secured tothe shaft). In accordance with the present invention, it is the balloonitself that is multi-lumen. It is believed that there are manyapplications where an inflatable balloon having multiple, distinctchannels or lumens that are formed as a part of the inflatable balloonwould be very desirable. As used herein, the terms “balloon” and“balloon lumen” therefore mean a thermoplastic tubular segment havingthe properties of being very thin-walled (less than 0.0015 inchesthick), high strength, flexible, readily inflatable under apredetermined range of fluid pressures, and readily collapsible undervacuum. It is also typical for such balloons to have at least onetapered end, although according to the present invention it is notnecessary. For high strength, these balloons are normally expanded andoriented in at least one direction and preferably in two directions,i.e. biaxial orientation. Orientation occurs when a thermoplasticmaterial is expanded or stretched under certain conditions with theresult that the material has a much greater strength than beforeexpansion. Such balloons, and methods of preparing them, are describedin U.S. Pat. No. 4,820,349 (Saab), U.S. Pat. No. Re. 32,983 (Levy), andEuropean Patent Specification No. 0274411 (Saab), which are incorporatedherein by reference. For some applications, a balloon segment having thegeneral properties described above can be affixed to an elongated,relatively thick-walled (0.002 inches or thicker) catheter shaft. Forother applications, the elongated, thin, side walls of the balloon canserve as the catheter shaft when the balloon is inflated.

The multi-lumen balloons of the present invention are distinguished fromthe multi-lumen balloon catheters of the prior art, as discussed above,in that the walls defining the lumens are formed as an integral part ofthe balloon. As used herein, the terms “integral part” and “integrallyformed” each mean that each lumen of the multi-lumen balloon shares acommon wall portion with part of at least one balloon lumen. Bycontrast, the prior art shows lumens that are integrally formed as apart of a conventional catheter shaft and are defined by relativelythick walls of that shaft (e.g. Segal et al.), catheter lumens thatcommunicate with or terminate in a balloon segment (e.g. Banka and Segalet al.), and lumens in a shaft that passes coaxially through a balloonsegment (e.g. Banka). The relatively thick walls that define the lumensof conventional multi-lumen catheter shafts typically range from about0.002-0.010 inches in wall thickness and, in any event, are not hightensile strength or readily inflatable under fluid pressure, nor arethey readily collapsible under vacuum when operating at the pressuresfor which the device is designed. Most balloon catheter shafts are madeby extrusion of a thermoplastic material. The resulting shafts aretypically not substantially oriented, therefore not high tensilestrength. Such balloon catheter shafts are not inflatable as balloons atpressures at which the balloons typically operate, for the obviousreason that the shafts are supposed to remain stiff, and not inflate ordeflate. Thus, the multi-lumen catheters of the prior art cannot, bythemselves, function as balloons. As a result the design of multi-lumencatheters which use balloons has been limited because these featuresprovide design constraints.

For example, a perfusion-catheter utilizes a balloon to perform anangioplasty procedure to dilate coronary arteries which are partiallyclosed due to arteriosclerosis. While this procedure is often effectivein relieving the symptoms caused by the disease by dilating the bloodvessels for a substantial length of time, it will be evident that theballoon itself will occlude the blood vessel while it is inflated withinthe vessel. Accordingly, perfusion catheters are equipped with at leastone additional lumen extending through the catheter shaft. The shaft isprovided with openings that communicate with this additional lumen onopposite sides of the balloon (the sides of the shaft both distal andproximate from the balloon) so that blood will flow though the lumenwhen the balloon is inflated reducing the risks to the patient. However,the shaft is typically of a small cross-sectional diameter, with theperfusion lumen being even smaller so that blood flow is stillsubstantially reduced.

These and other limitations of the prior art catheters are overcome withthe multi-lumen balloons of this invention.

OBJECTS OF THE INVENTION

Accordingly, it is a principal object of this invention to providemulti-lumen balloons for use as, or in conjunction with, ballooncatheters.

It is also an object of this invention to provide a multi-lumen balloonwherein the walls of the lumens are integrally formed as a part of theballoon.

A further object of this invention is to provide multi-lumen balloonswherein the lumens may be open or closed ended, of varying sizes andgeometries, and may begin and end at varying longitudinal positionsalong the axes of the balloons.

Another object of this invention is to provide multi-lumen balloonswherein the individual lumens may be utilized, among other things, fordrainage; for circulating heat transfer fluids; for housing electricalor guide wires or laser fibers; for accessing internal body locationswith fluids, medicine, drugs, or medical instruments; and forfacilitating passage of fluids, such as blood, around an obstructionincluding the balloon itself.

Still another object of this invention is to provide multi-lumenballoons wherein the materials used to form the individual lumens mayhave different physical and/or chemical properties from each other.

Yet another object of this invention is to provide methods of preparingmulti-lumen balloons in accordance with this invention.

And still another object of the present invention is to provide animproved balloon catheter provided with a multi-lumen balloon asdescribed.

These and other objects and advantages of this invention will be betterunderstood from the following description, which is to be read togetherwith the accompanying drawings.

SUMMARY OF THE INVENTION

The balloon of the present invention comprises thin walled, inflatable,flexible, thermoplastic tubular material formed so as to define at leasttwo separate channels or lumens integrally formed with one another. Atleast one of the lumens can be inflatable with a fluid. Such balloonscan be prepared by a blow molding process utilizing multi-lumen tubingor preforms. Alternatively, an outer balloon segment can be formed byblow molding the segment from tubing or a preform in a mold. Formingwires or mandrels can then be positioned in contact with the innersurface of the outer balloon and a second tube or preform is blown intocontact with the inner wires or mandrels and the inner surface of theouter balloon segment. The balloons also can be fabricated by heatshrinking a heat-shrinkable thermoplastic film or tubing over one ormore forming wires or mandrels positioned along an outer wall of aninner balloon preform, or by heating and expanding thermoplastic tubingalong an inner wall of a balloon. Additionally, the blow molding andheat shrinking processes can be combined. Depending on the fabricationprocess selected, the lumens can be located inside or outside theballoon and made open or closed ended, of varying sizes and geometries,positioned at different locations along the balloon, and havingdifferent physical and/or chemical properties.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial isometric view of a three-lumen tube or preform;

FIG. 2 is a partial isometric view of a three-lumen balloon prepared byblow molding the preform of FIG. 1;

FIG. 3 is an isometric view of a balloon with three forming wires ofvarying lengths positioned longitudinally along the exterior of theballoon wall and with a surrounding heat-shrinkable tube shown in dottedoutline;

FIG. 4 is an isometric view of the balloon of FIG. 3 following the heatshrinking process to create three perimetrical lumens following theremoval of the forming wires and forming ribbed protrusions from theexterior wall of the balloon;

FIG. 5 is a cross-sectional view of the three-lumen balloon of FIG. 4along the line 5-5;

FIG. 6 is an isometric, view of a multi-lumen balloon formed with ahelical perimetric lumen having pin holes for delivering fluid to a bodycavity;

FIG. 7 is an isometric view of an outer balloon with three forming wiresof varying lengths positioned longitudinally along the interior of theballoon wall and with a preform tube shown within the outer balloon indotted outline;

FIG. 8 is an isometric-view of the balloon of FIG. 6 following the heatexpansion of the inner preform to create three interior, perimetricallumens following the removal of the forming wires;

FIG. 9 is a cross-sectional view of the three-lumen balloon of FIG. 8along the line 9-9;

FIG. 10 is a cross-sectional view of a balloon enclosing three sectionsof expandable tubing;

FIG. 11 is a cross-sectional view similar to FIG. 10, but showing theballoon following expansion of the tubing to form three substantiallycircular interior lumens and one irregularly-shaped interior lumen;

FIG. 12 is an isometric view of one embodiment of a perfusion catheterincluding a multi-lumen balloon made in accordance with the presentinvention;

FIG. 13 is a cross-sectional view taken along section line 13-13 of themulti-lumen balloon shown in FIG. 12, wherein the balloon is madeaccording to one method of the present invention; and

FIG. 14 is a cross-sectional view taken through a section line similarto section line 13-13 of the multi-lumen balloon shown in FIG. 12,wherein the balloon is made according to another method of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

In all of the drawings, as described below, it should be understood thatthe wall thicknesses have been greatly exaggerated relative to otherelements and dimensions for purposes of illustration.

FIG. 1 shows a partial isometric view of a thermoplastic tube or preform10 comprising three independent preform channels or lumens 12, 14 and16. Thermoplastic preforms such as that illustrated in FIG. 1 are thestarting point for one method of preparing multi-lumen balloons inaccordance with this invention. Such multi-lumen preforms can beprepared using conventional technologies such as extrusion. Theextrusion method can be used to produce tapered lumen sections.Co-extrusion of various materials is also well known in the art and canbe used to produce preforms suitable for this invention. Additionally,extrusion techniques that allow one to open and seal off a lumen so thatthe lumen can start and stop at any selected axial location can be usedto produce suitable preforms. As shown in FIG. 1 for illustrativepurposes, the three preform lumens 12, 14, and 16 are shaped so thateach of the walls are of a thickness substantially in proportion to thefinal thickness of the walls of the formed lumens after the balloon isformed. The thickness of the walls of the tubular material of thepreform can be the same as that typically employed for catheter shafts,between about 0.002 and 0.010 inches, although this can vary. Thesewalls include the cylindrical wall 18, as well as the interior walls 20,which may or may not be radially directed. In this example, thecylindrical wall 18 may be thicker than the interior walls when it isdesired that the final wall thickness of the cylindrical wall of theballoon is to be thicker. The geometry of the preform and the preformlumens determines, at least in part, the geometry of the resultingmulti-lumen balloons. It will be understood that, depending on the typeof multi-lumen balloon desired, the starting preform can be selected tohave more or less than three preform lumens (with a minimum of twolumens), lumens of varying dimensions, and lumens with taperedsidewalls. Such different preforms can be prepared with well knowntechnologies.

Blow molding a portion of the preform 10 of FIG. 1 in accordance withconventional balloon fabrication techniques, for example as described inU.S. Pat. No. 4,820,349 (Saab), U.S. Pat. No. Re. 32,983 (Levy), andEuropean Patent Specification No. 0274411 (Saab), results in a verythin-walled, flexible, high strength, multi-lumen balloon 22 as shown inFIG. 2. In the course of the blow molding operation, preform lumens 12,14 and 16 of FIG. 1 are oriented into three very thin-walled, flexible,high strength balloon lumens 24, 26 and 28 respectively, each integrallyformed with at least a portion of one wall of another balloon lumen andpreferably, although not necessarily, running the length of the balloon(including its tapered end or ends if the balloon is provided with one,similar to that shown in FIG. 3). In the embodiment shown, all of thewalls are sufficiently thin, i.e., 0.0015 inches or less so that thelumens are each selectively inflatable, although as stated above it ispossible that, for some applications, one or more of the walls is of athickness greater than 0.002 inches so that fewer than all of the lumensare inflatable. It will be understood that the diameter of balloon 22,when fully expanded, will be substantially greater than the startingdiameter of preform 10 (typically 2-6 times greater).

The foregoing method for preparing multi-lumen balloons in accordancewith this invention is especially well suited to producing lumens thatrun along the entire axial length of the balloon and in situations whereprecise lumen geometry is not critical. In addition, this process canproduce the thinnest and most flexible multi-lumen balloons because thewalls are each of a single wall thickness, rather than portions of thewalls having the thickness of a double wall as results from thealternative embodiment described below.

FIGS. 3-5 illustrate an alternative embodiment of this invention whereinmulti-lumen balloons are prepared by heat-shrinking a thermoplastic filmor thin-walled tubing over one or more forming wires or forming mandrelspositioned along an outer wall of a previously-formed balloon 40. Thepreviously formed balloon can be formed in a mold so as to form thecontinuous structure shown and described below in connection with FIG.3. However, the starting balloons for this embodiment of the inventioncan be prepared by any conventional technique, such as that described inU.S. Pat. No. 4,820,349 (Saab), U.S. Pat. No. Re. 32,983 (Levy), andEuropean Patent Specification No. 0274411 (Saab). A mandrel (not shown)may be positioned inside the balloon for support. Alternatively theballoon may be filled with a pressurized fluid for support.

Thus, forming wires or mandrels 42, 44 and 46 in FIG. 3, are positionedin a longitudinal direction along the outer wall of balloon 40. As seenin FIG. 3, the wires may be of varying lengths and may start and end atdifferent longitudinal locations along the axis of the balloon. Forexample, in FIG. 3, forming wire 42 runs the entire length of theballoon 40 including the working section 48 and the tapered ends ortransition cones 50, and will create a lumen 52, as best seen in FIG. 5,that also runs the length of the balloon including the conical ortapered ends 50. Forming wire 44, on the other hand, runs from one endof the balloon across working section 48 and will create a correspondinglumen 54 as seen in FIG. 5. Finally, forming wire 46 begins and endsalong the outer wall of the balloon within working section 48 withouteither end of wire 46 extending to an end of the balloon, therebycreating a corresponding lumen 56 as seen in FIG. 5. The forming wiresmay be of the same or different diameters, and may be of a uniformedcross-section or a non-uniformed cross-section such as a taper, and maybe of circular or other cross-sectional shape, depending on the desiredlumen geometry. Thus, for example, this method permits the manufactureof balloons with lumens of generally circular, ovular, triangular orrectangular cross-sections to accommodate different needs. The geometriccross-section of each wire can also change in cross-sectional size orshape along its length as may be required for a particular application.

When the forming wires have been properly positioned along the outerwall of balloon 40, suitably held in place for example by properplacement within a fixture, a tube 60 of a heat-shrinkablethermoplastic, such as a biaxially-oriented polyethylene terephthalate,having a diameter somewhat greater than that of balloon 40 is slippedover the balloon and the forming wires. The actual diameter of the tube60 should be as close as possible to the final dimension to maintain thestrength. A suitable tool, such as a mandrel can be secured within theinner balloon 40 so that the latter maintains its shape. Alternatively,the balloon may be filled with a pressurized fluid for support. Whentube 60 is subjected to heat treatment, the tube shrinks to come intointimate contact with and conform to outer wall 48 of balloon 40, exceptwhere forming wires 42, 44 and 46 cause tube 60 to conform outwardlyfrom the outer wall of the balloon as it forms around the wires therebycreating lumens 52, 54 and 56 respectively, each integrally formed withthe wall 48 of the balloon 40. The balloon and tube can but need not bebonded together using a suitable adhesive, such as a solvent-basedflexible polyester hot melt adhesive. Removal of wire 42 leaves a lumen52 open at both ends. Removal of wire 44 can leave a lumen 54 open atone end and closed at the other. Removal of wire 46 requires cuttingopen at least one closed end of lumen 56.

The foregoing method of preparing multi-lumen balloons in accordancewith this invention is the preferred embodiment in most cases forproducing perimetrical lumens forming ribbed protrusions from theexterior wall of the multi-lumen balloon. Such a design is useful wherethe multi-lumen balloon is to be inserted in a body lumen, and the mainlumen formed by the inner balloon 40 is inflated such that inflation ofthe balloon 40 will have little or no effect on the pressure within theperimetric lumens 52, 54 and 56 protruding from the outer surface of thefinal multi-lumen balloon design because balloon 40 is substantiallyinelastic. This embodiment also illustrates that at least some of thelumens do not need to run the entire length of the balloon. This is alsothe preferred embodiment where relatively precise lumen geometry anddimensions are important. Selection of the mandrels or forming wires inthis embodiment permits relatively precise control over the size, shapeand location of the lumens and makes the results highly reproducible.This embodiment also facilitates producing lumens with somewhatdifferent properties than the balloon. For example, for manyapplications it may be desirable to use a balloon 40 of high strengthPET, but to choose a tube 60 made of thin-walled, heat-shrinkablepolyethylene which would create polyethylene lumens and a very lowfriction outer shell for the multi-lumen balloon. The tubing 60 on theother hand can be made of biaxially oriented polyethylene terephthalate.

This embodiment of the invention also makes it possible to easily form aballoon having a perimetrical lumen 62 running, for example, in ahelical pattern around the cylindrical wall of the balloon 64, as bestshown in FIG. 6. Such a spiral perimetrical lumen can contain pinholes66 along its length and can be used to precisely deliver medications orother fluids to select locations within the body cavity within which theballoon is placed, while at the same time independently providingballoon dilatation obviously, the geometric shape of such a lumen neednot necessarily be helical, but can assume any conceivable shape for theparticular application for which it is to be used.

FIGS. 7-9 show a method of making a multi-lumen balloon 70 having threeperimetrical lumens which protrude inwardly into the larger lumen.Forming wires of varying lengths may be positioned longitudinally alongthe interior of the balloon wall and with a preform tube 90 shown withinthe outer balloon 80 in dotted outline. In this embodiment the outerballoon 80 is preformed in the same manner as was inner balloon 40 shownin FIGS. 3-5. The balloon can be blown in a mold where it is ready toreceive the wires 72, 74 and 76 (which are comparable to wires 42, 44and 46, respectively) and the inner preform tube 90. In this instancethe inner tube 90 is blown so that it comes into contact with the wiresand the inner surface of the balloon 80. The two pieces can but need notbe secured together and the wires 72, 74, 76 removed in the same manneras described in connection with FIGS. 3-5 so as to form threeperimetrical lumens 82, 84 and 86, all protruding inwardly. In thisembodiment, inflation of the expanded inner tube 90 of the resultingmulti-lumen balloon will tend to collapse and squeeze the smaller lumens82, 84 and 86. This embodiment can be used, for example, to “clamp” downon an object, such as a guide wire or fiber optic, during inflation ofthe balloon.

Still another embodiment of this invention is illustrated in FIGS. 10and 11 wherein multi-lumen balloons are prepared by heating andexpanding one or more sections of thermoplastic tubing within the innerwall of a preformed balloon. The starting balloons for this embodimentof the invention can be prepared by any conventional technique, such asthat described in U.S. Pat. No. 4,820,349 (Saab), U.S. Pat. No. Re.32,983 (Levy), and European Patent Specification No. 0274411 (Saab).Thus, in FIG. 10, tubing sections 100, 102 and 104 are positioned insideballoon 106 defined by inner wall 108. Upon expansion of tubing sections100, 102 and 104, as seen in FIG. 11, they create respectively generallycircular lumens 110, 112 and 114, defined respectively by walls 111, 113and 115. Walls 111, 113 and 115, together with inner wall 108, define anirregularly-shaped balloon lumen 118. This method for preparingmulti-lumen balloons is useful for producing interior lumens and whereinit is desired to have lumens with different physical and/or chemicalproperties from the balloon or from each other or both.

EXAMPLE

A 4 mm balloon with only one tapered end was fabricated from PET usingconventional techniques. The balloon was placed over a mandrel forsupport and a wire rod (0.028″ diameter) was laid up against the outsideof the balloon. A piece of biaxially-oriented, thin walled, highstrength polyester shrink tube was placed over the entire assembly andshrunk over the balloon and wire. The assembly was cooled and the wireand support mandrel removed resulting in a 4 mm balloon with an 0.028″“side lumen” on the outside of the balloon. In this case the placementof the wire end determined where the lumen ended along the balloon.

The multi-lumen balloon/catheter constructions of this invention can beused with virtually any catheter or balloon/catheter design includingover the wire, fixed wire, rapid exchange, and other conventional aswell as non-traditional catheter designs. In addition, the multi-lumenballoons of this invention facilitate the production of an entirely newand distinctive generation of catheter designs.

One example of the many benefits of this invention is in balloonangioplasty, which involves inserting a balloon dilatation catheter intoa coronary artery that contains an occluded section and inflating theballoon segment at the occlusion site to open a larger arterialpassageway. During the inflation procedure, blood flow in the damagedartery is temporarily blocked by the inflated balloon, which can behazardous or fatal and therefore limits the dilatation time. Toalleviate this problem and extend dilatation time to improveeffectiveness, so-called perfusion catheters have been developed whereinholes in the catheter shaft on either side of the balloon permit a smallvolume of blood to enter the interior of the catheter shaft, by-pass theballoon, and exit the catheter shaft on the other side.

Because of the relatively small diameter of the catheter shaft, however,the volume of blood that can by-pass the balloon in this fashion isminimal unless the shaft is very large. However, such larger diametershafts have increased profiles and stiffness; and, as a result, theexisting perfusion catheters are of limited utility. By contrast, withthe multi-lumen balloons of this invention, one or more interior balloonlumens can be utilized to open a by-pass almost as large as the blockedartery itself, thereby greatly increasing blood flow and extendingdilatation time. Indeed, once in place, a multi-lumen balloon used inthis manner could be kept inflated for days and act as a temporarystent.

For example, in FIGS. 12-14, a perfusion catheter 120 is designed with amulti-lumen balloon 122 in accordance with the principles of the presentinvention. In this design, the catheter shaft 124 is of a conventionaldesign, except that it does not have to be provided with lumens forallowing for blood flow when the balloon is inflated. Instead theballoon is formed as a multi-lumen balloon in accordance with thepresent invention for providing the necessary blood flow, and forproviding the necessary inflation so as to achieve dilatation of theblood vessel. As seen in FIG. 13, center lumen 132 receives the cathetershaft 124 so that the balloon can be secured in place with a suitableadhesive to the shaft. At least four lumens 126, 127, 128 and 130 areradially spaced around center lumen 132 for receiving the pressurizedfluid for inflating each of these lumens so as to achieve dilatation ofa blood vessel. The lumens 126, 127, 128 and 130, must be closed orconnected and be adapted to be in fluid communication with a source ofpressurized fluid. Lumens 134, 135, 136 and 138, are-formed within thespaces between lumens 126, 127, 128 and 130, and the corresponding wallsections 140, 143, 142 and 144, when lumens 126, 127, 128 and 130 areinflated. Lumens 134, 135, 136 and 138 are open at both the proximal anddistal ends so that when lumens 126, 127, 128 and 130 are inflated withpressurized fluid, the wall sections 140, 143, 142 and 144 will becomesufficiently taut so as to open lumens 134, 135, 136 and 138 and so asto allow blood to flow through these lumens. It should be appreciatedthat this catheter design can be used for other applications, forexample where it is desirable to flush an area of the body cavity distalwith respect to the balloon. In this case one of the lumens 134, 135,136 or 138 can be used, or an additional lumen can be formed, so as todeliver the flushing fluid to the particular location of the bodycavity, while the opened lumens allow for the flushing fluids to beeasily removed.

The multi-lumen balloon for this embodiment can be made from two pieces,as shown in FIG. 13, or from a single integral piece, as illustrated inFIG. 14. The structure as shown in FIG. 13 can be prepared either byheat-shrinking a thermoplastic sleeve over the three-lobe interiorstructure (made by blow molding a five-lumen extruded preform ofappropriate starting geometry in accordance with this invention) or byblow molding an extruded preform inside the thermoplastic sleeve. Thestructure as shown in FIG. 14 can be prepared by blow molding anine-lumen extruded preform of appropriate starting geometry inaccordance with this invention.

The multi-lumen balloons of this invention are also useful, for example,for producing guide wire lumens such that the guide wire need not passthrough the catheter shaft and extend through the balloon interior, asis the case with typical prior art structures. Instead, with themulti-lumen balloons of this invention, the guide wire can be run, forexample, in a secondary side lumen formed along the wall of the balloonand extending to a location distal with respect to the balloon.

One or more of any balloon materials can be used for the multi-lumenballoons of this invention including PET or other polyesters, nylon,PVC, polyethylene, etc. Thin-walled, high strength balloons such as PET,are preferred in most applications in order to minimize the overallprofile (build up of wall thicknesses) of the final catheter devices.

The multi-lumen balloons of this invention can be used either bythemselves as balloon dilatation catheters or as the balloon segment ofa conventional balloon catheter. For example, one end of a balloonhaving two secondary lumens in accordance with this invention can bebonded to the distal end of a three lumen catheter such that eachcatheter lumen is in communication with the balloon or one of thesecondary lumens respectively. The catheter lumen in communication withthe balloon is used to inflate or deflate the balloon. A catheter lumenin communication with one of the secondary lumens can provide the accessfor fluids, drugs, a guide wire, laser or optical fibers, sensors, etc.For some applications, it may be desirable to bond both ends of themulti-lumen balloon to catheter segments having catheter lumens, forexample for delivering medication, blood or other fluids to a pointbeyond an obstruction. In this case, a balloon having a secondary lumenthat runs the length of the balloon and has two open ends can beconnected to two catheter segments such that the proximal end of thesecondary lumen communicates with a first catheter lumen and the distalend of the secondary lumen communicates with a second catheter lumen.

Other beneficial applications for the lumens of the multi-lumen balloonsof this invention-include: means for additional dilatation of a bodycavity by inflating and deflating secondary, tertiary or other balloonlumens; providing working channels to contain sensors, such asthermocouple or fiber optics, or to house guide wires; channels for thedelivery of fluids, medicine or drugs to the area under the balloon orto regions beyond the balloon; working channels to house laser oroptical fibers or a heating wire used to cauterize tissue; channels usedfor biopsy or other sampling procedures; channels used for drainage, forexample as a urology drain; and channels used to circulate heat transferfluids for cooling or heating purposes, such as freezing of select areaswith liquid nitrogen or heating select areas with-heated fluid such aswater or saline.

For example, with the multi-lumen balloons of this invention, a primaryballoon lumen can be used for inflation while smaller, secondary lumenscan contain a guide wire, thermocouple, laser fiber or optical fiber. Inanother example, a primary balloon lumen can be used to dilate a bodycavity to a first size and shape; then, by dilating a secondary balloonlumen, the body cavity can be dilated to a second size or shape. For thelatter embodiment, the secondary lumen must also have the generalproperties of a balloon, i.e., very thin-walled, flexible, highstrength, readily inflatable under fluid pressure, and readilycollapsible under vacuum.

As described above, depending on the method of fabrication, the lumenscan be virtually any length, traveling from one end of the balloon tothe other, or starting anywhere along the length of the balloon andending anywhere. The lumens can be open or closed ended. The lumens canbe made in a variety of shapes or cross-sections to accommodatedifferent needs.

Since certain changes may be made in the above-described apparatuses andprocesses without departing from the scope of the invention hereininvolved, it is intended that all matter contained in the abovedescription shall be interpreted in an illustrative and not in alimiting sense.

1. Medical apparatus for use as or in combination with a ballooncatheter, said apparatus comprising a balloon including integrallyformed wall means for defining at least two separate lumens.
 2. Medicalapparatus according to claim 1 wherein at least some of said wall meansincludes properties of being very thin-walled, flexible, high strength,readily inflatable under fluid pressure, and readily collapsible undervacuum.
 3. Medical apparatus according to claim 2 wherein at least someof said wall means has a thickness of less than 0015 inches.
 4. Medicalapparatus according to claim 2 wherein at least some of said wall meanshas been expanded and oriented in at least one direction.
 5. Medicalapparatus according to claim 4 wherein at least some of said wall-meanshas been biaxially oriented.
 6. Medical apparatus according to claim 1wherein a first lumen of said separate lumens comprises a balloon lumen.7. Medical apparatus according to claim 6 wherein said integrally formedwall means also defines a second lumen such that said second lumen hasat least one closed end.
 8. Medical apparatus according to claim 6wherein said integrally formed wall means also defines a second lumensuch that said second lumen has at least one closed end and an open end.9. Medical apparatus according to claim 6 wherein said integrally formedwall means also defines a second lumen such that said second lumen hastwo open ends.
 10. Medical apparatus according to claim 6 wherein saidintegrally formed wall means also defines a second lumen such that saidsecond lumen runs the length of said balloon.
 11. Medical apparatusaccording to claim 6 wherein said integrally formed wall means alsodefines a second lumen such that said second lumen begins at one end ofsaid balloon and ends before reaching the opposite end of said balloon.12. Medical apparatus according to claim 6 wherein said integrallyformed wall means also defines a second lumen such that said secondlumen is shorter than said balloon and does not extend to either end ofsaid balloon.
 13. Medical apparatus according to claim 6 wherein saidintegrally formed wall means also defines a second lumen such that saidsecond lumen has a generally circular cross-section.
 14. Medicalapparatus according to claim 6 wherein said integrally formed wall meansalso defines a second lumen such that said second lumen has a generallyovular cross-section.
 15. Medical apparatus according to claim 6 whereinsaid integrally formed wall means also defines a second lumen such thatsaid second lumen has a generally triangular cross-section.
 16. Medicalapparatus according to claim 6 wherein said integrally formed wall meansalso defines a second lumen such that said second lumen has a generallyrectangular cross-section.
 17. Medical apparatus according to claim 6wherein said integrally formed wall means also defines a second lumensuch that said second lumen has a cross-section that tapers from largerto smaller along the length of said second lumen.
 18. Medical apparatusaccording to claim 6 wherein said integrally formed wall means alsodefines a second lumen such that said second lumen has a cross-sectionthat changes in shape along the length of said second lumen.
 19. Medicalapparatus according to claim 1 wherein all of said wall means includesthe properties of being very thin-walled, flexible, high strength,readily inflatable under fluid pressure, and readily collapsible undervacuum.
 20. Medical apparatus according to claim 19 wherein all of saidwall means has been biaxially oriented.
 21. Balloon dilatation catheterapparatus comprising an elongated catheter and a balloon includingintegrally formed wall means for defining a balloon lumen incommunication with a first catheter lumen so that fluid can betransferred between said first catheter lumen and said balloon lumen sothat said balloon can be inflated and collapsed, said integrally formedwall means also defining at least one secondary lumen.
 22. Catheterapparatus of claim 21 wherein said integrally formed wall means alsodefines at least one of said secondary lumens having a proximal end incommunication with a second catheter lumen, a closed distal end, andhaving the properties of being very thin-walled, flexible, highstrength, substantially inelastic, readily inflatable under fluidpressure, and readily collapsible under vacuum.
 23. Catheter apparatusof claim 21 wherein said integrally formed wall means also defines atleast one of said secondary lumens having a proximal end incommunication with a second catheter lumen and an open distal end. 24.Catheter apparatus of claim 21 wherein said integrally formed wall meansalso define at least one of said secondary lumens having a proximal endin communication with a second catheter lumen and a distal end incommunication with a third catheter lumen.
 25. Catheter apparatus ofclaim 21 wherein said integrally formed wall means also define at leastone of said secondary lumens having an open, unobstructed proximal endand an open distal end.
 26. Medical apparatus for use as or incombination with a balloon dilatation catheter made by the method ofblow molding a thermoplastic tube having a plurality of open channels soas to expand and orient the polymer in at least one direction to form atubular balloon segment comprising multiple lumens integrally formedwith one another.
 27. Medical apparatus according to claim 26 whereinsaid tube is blow molded so as to biaxially orient said polymer. 28.Medical apparatus of claim 26 wherein said lumens are very thin-walled,flexible, high strength, substantially inelastic, readily inflatableunder fluid pressure, and readily collapsible under vacuum.
 29. Medicalapparatus for use as or in combination with a balloon dilatationcatheter made by the method of heat-shrinking a thin-walledthermoplastic film over an assembly comprising a tubular balloon withone or more forming mandrels positioned adjacent an outer wall of saidballoon and removing said forming mandrels to leave a number of lumenscorresponding to the number of forming mandrels, each said lumen beingintegrally formed with said outer wall.
 30. Medical apparatus for use asor in combination with a balloon dilatation catheter made by the methodof expanding a thin-walled thermoplastic film inside an assemblycomprising a tubular balloon with one or more forming mandrelspositioned adjacent an inner wall of said balloon and removing saidforming mandrels to leave a number of lumens corresponding to the numberof forming mandrels, each said lumen being integrally formed with saidinner wall.
 31. Medical apparatus for use as or in combination with aballoon dilatation catheter made by the method of expandingthermoplastic tubing along an inner wall of a tubular balloon to formone or more interior lumens, each said lumen being integrally formedwith said inner wall.